voronoi fast.f90 and voronoi small memory.f90 are two variants to do a voronoi tessellation and write the result to a mesh file that can be interpreted by mpie_spectral.f90. Difference is the memory management resulting in one faster and one memory saving version. voronoi fast.f90 has also the ability to write out a file for Ricardo Lebensohns spectral code.
colormap.f90 is a simple code that can be used to generate colormaps for gmsh.
Only grainId is used, physical dimension and subdivisions need to be provided on command line.
improvement possible by parsing x, y, z columns to get those directly.